(1.) Field of the Invention
The present invention relates to a transportable fluid jack, in particular a transportable fluid jack apparatus comprising a load platform that is selectively raised and lowered by a bellows type expandable bag. The bag is selectively supplied with pressurized fluid from a self-contained source of pressurized fluid supported on the jack to raise the load platform, and is selectively exhausted of pressurized fluid filling the bellows bag to lower the load platform.
(2) Description of the Related Art
Various types of lifting devices are known in the prior art and many of these known devices are portable. Some of the portable lifting devices employ inflatable air bags that extend vertically when inflated and impart a lifting force to an object to be raised by the device. The inflatable bags are then exhausted and deflated, causing the bag to collapse vertically and lower the object lifted by the air bag.
A disadvantage often encountered in these types of lifting devices is that the inflatable air bags employed to exert the lifting force are not of themselves laterally stable. Lifting devices employing inflatable air bags often require additional support structure surrounding the lifting bag to resist any excessive side to side lateral movement of an object being raised. For example, if the load raised by the lifting bag is distributed unevenly on the bag it could cause the bag to collapse over on one side. Additional support structure is needed to prevent this occurrence. The additional lateral supporting structure of the prior art devices often makes the jack device cumbersome, and the vertical dimensioning of the support structure often limit the environments in which the device may be used. The lateral support structures are constructed to collapse or fold downward as the inflatable air bag is deflated. However, some support structures, even when collapsed, require a certain vertical clearance before the collapsed lifting device can be inserted beneath an object to be lifted.
Another disadvantage often encountered in the use of lifting jacks of the type employing an inflatable air bag is that they require a separate source of pressurized fluid to fill the bag and raise the lifting device. This limits the applications in which the inflatable bag type of lifting device may be used. Prior art inflatable bag lifting devices often may only be used in areas where there is access to a separate source of compressed fluid to fill the lifting inflatable bag, or there is access to a separate power source to operate a pump supplying pressurized fluid to the inflatable bag.
It is an object of the present invention to overcome these shortcomings of prior art inflatable bag lifting devices by providing a transportable fluid jack apparatus that includes a vertical support structure for a lifting inflatable bag that does not interfere with the insertion of the lifting bag beneath an object to be lifted, and also includes its own self-contained source of pressurized fluid and does not rely on external sources of pressurized fluid or power to operate the inflatable bag of the apparatus.